Preparation of organometallic amide compositions

ABSTRACT

This invention concerns organometallic amide compositions particularly bimetallic organoamides in liquid hydrocarbon solutions in which one metal is an alkali metal the other an alkaline earth metal, zinc or copper and particularly lithium magnesium bis-diorganoamides, such as lithium magnesium bis-diisopropylamide and processes for preparation of such amides. These novel bimetallic amides have increased solubility in liquid hydrocarbon solvents and improved thermal and precipitation stability at temperatures of 0° C. to 40° C.

The present invention concerns novel mono- and bimetallic organoamidecompositions, their stable solutions in liquid hydrocarbon solvents, andin hydrocarbon solvents containing small amounts of a Lewis base andimproved methods for their production.

The bulky organoamides of alkali metals are used extensively as reagentsin organic synthesis by virtue of the combination of their strongBronsted basicity and low nucleophilicity. Lithium organoamide compoundssuch as lithium diisopropylamide (LDA), lithium pyrrolidide (LPA), andlithium hexamethyldisilazide (LHS) are essentially insoluble in Lewisbase-free hydrocarbon solvents. Although these compounds are soluble inethers, they are quite unstable with time even at room temperature.Thus, users of these compounds (especially LDA) prepare their ownrequirements immediately before use by the reaction of a pyrophoricsolution of n-butyllithium with amine in ether medium or reaction oflithium metal with diisopropylamine in ether medium.

Lithium diisopropylamide (LDA) has previously been synthesized byreacting lithium metal and styrene with diisopropylamine in ethyl ether(R. Reetz and F. Marrier, Liebigs Am. Chem., 1471, 1980). However, LDAin ether solvents is not stable. Further modifications were reported andpatented in the synthesis of a "stable" solution of LDA in hydrocarbonsolvent containing a limited amount of THF by Morrison et al. (U.S. Pat.No. 4,595,779, June 17, 1986). The main drawback of LDA in ethersolution or in a hydrocarbon solution containing even limited THF (i.e.,≦1.0 mole/mole LDA) is its limited thermal stability. These solutions ofLDA complexed with limited THF (≦1.0 mole/mole LDA) do lose asignificant amount of their activity (25 to 50%) on storage at 30°C.-40° C. for 30 days, although no loss is detected at 0° C. to 10° C.Crystallization occurs from solution at ≦0° C. when the concentration ofLDA and THF is 2.0 molar. Thus, there continues to be a demand fororganometallic amide solutions in hydrocarbon solvents with improvedthermal stability.

The present invention provides stabilized, nonpyrophoric solutions of analkali metal diorganoamide in a liquid hydrocarbon solvent containing aLewis base, such as tetrahydrofuran, and 1 to 10 mole percent of ametallic diorganoamide. These compositions are conveniently representedas a composition of the formula:

    M.sub.x.sup.a M.sub.y.sup.b (M.sup.c RR').sub.z.nLB.mM.sup.d X

wherein

M^(a) =alkali metals (gr IA the Periodic Table, e.g., Li, Na, K . . . )

M^(b) =alkaline earth metals (gr IIA of Periodic Table, such as Mg, Ca,Ba, Sr, and also other metals such as Zn, Al, and Cu)

M^(c) =N, P, and As

M^(d) =lithium

R=alkyl, cycloalkyl, aryl, alkylaryl, aralkyl, trialkylsilyl,heteroalkyl, heteroaryl, etc.

R'=alkyl, cycloalkyl, aryl, alkylaryl, aralkyl, trialkylsilyl,heteroalkyl, heteroaryl, and hydrogen . . .

X=halogen (Cl, Br, I), trifluoromethylsulfonyl, p-methylbenzenesulfonyl(p-tosyl), and perchlorate (ClO₄)

m=0 to 2

n=>0 and <4.0

x+y=1

z=x+(y multiplied by the valence of metal M^(b))

LB=Lewis base such as tetrahydrofuran (THF), methyl THF, dimethyl ether,diethyl ether, dibutyl ether, tertiary amines such as trimethylamine,triethylamine, tetramethylethylenediamine . . .

The Lewis base to amide ratios are critical to the solubility andstability of the compositions represented by the foregoing formula. Ingeneral, 1 to 2 moles of Lewis base, such as THF, will solvate each moleof bimetallic diorganoamide. An additional important aspect of thisinvention is the discovery that a lithium halide dissolved in thebimetallic diorganoamide solution increases solution stability of thediorganoamide. However, two moles of Lewis base are necessary todissolve a mole of lithium halide. Many metallic diorganoamides, such asmagnesium bis-diisopropylamide, are hydrocarbon soluble. Thus, the ratioof M^(a) to M^(b) in the formula affects the amount of Lewis baserequired to dissolve a specific bimetallic diorganoamide.

The Lewis base to amide ratios in the foregoing formula are determinedby the value of n which must reflect the variables of the M^(a) to M^(b)ratio and whether lithium halide is included in the solution. When thereis no lithium halide in the solution the value for n can vary betweengreater than zero and less than three. The value for n when there is nolithium halide in a solution in a metallic diorganoamide solution isrelated to the value z so that n equals z multiplied by a value between1 to 2, i.e., n=z (1.5±0.5). When there is lithium halide in thesolution, the value of n is appropriately related to the value m so thatn is equal to m multiplied by the value of x plus 2, i.e., n=m(2+x).When the value for y is zero and a mono-metallic diorganoamidecontaining lithium halide is present, the value of n is equal to thevalue of m multiplied by two plus one, i.e., n=2m+1.

The process of this invention provides hydrocarbon solutions ofbimetallic organoamide compositions. Broadly, the process reacts ametallic bis-mono- or diorganoamide composition or anorganoamidometallic halide composition with an alkali metal and a mono-or diorganoamine at about 0° C. to about 50° C. in a hydrocarbon solventin the presence of an electron carrier and a Lewis base to produce thedesired bimetallic mono- or diorganoamide composition. One of the metalsis thus an alkali metal such as lithium, sodium or potassium and theother metal is selected from alkaline earth metals such as magnesium,calcium, barium, etc., and other metals such as zinc, aluminum andcopper.

One aspect of the invention begins with the preparation of an alkalineearth bis-diorganoamide, such as magnesium bis-diisopropylamide (MDA),which is to be employed in the subsequent preparation of the stablebimetallic diorganoamide compositions of the invention, such as, forexample, a lithium/magnesium diisopropylamide composition.

The preparation of said magnesium bis-diorganoamide can be accomplishedby a number of methods.

One novel method of this invention comprises reaction of magnesium metalwith n-butyl chloride in the presence of a stoichiometric amount ofdiisopropylamine in a hydrocarbon medium to yield a solid intermediateproduct, diisopropylamidomagnesium chloride, as shown in equation (1),in which "iPr" represents isopropyl.

    Mg+n-BuCl+(iPr).sub.2 NH→(iPr).sub.2 NMgCl↓+Butane↑(1)

The product is then reacted further with lithium metal, styrene orisoprene (as carrier for lithium in the reaction), and morediisopropylamine in the presence of not more than 0.5 moles oftetrahydrofuran (THF) per mole of lithium employed, to produce thedesired magnesium bis-diisopropylamide dissolved in the hydrocarbon(H.C.) solvent and a precipitate of lithium chloride as shown inequation (2). ##STR1##

The reaction of lithium metal, styrene and diisopropylamine produces "insitu" a soluble lithium diisopropylamide as the intermediate whichreacts with diisopropylamidomagnesium chloride to form soluble magnesiumbis-diisopropylamide and insoluble lithium chloride The requirement foruse of less than 0.5 moles of THF per mole of lithium metal used is toprevent solubilization of said lithium chloride in the solution ofmagnesium bis-diisopropylamide. Obviously the use of greater quantitiesof THF leads to the dissolution of all LiCl in the hydrocarbon solvent,also a novel aspect of this invention.

In order to eliminate the limitation for the requirement of <0.5 molesof THF/Li in the preparation of magnesium bis-diisopropylamide, one maysubstitute sodium metal for the lithium metal employed. The resultingsodium chloride by-product is insoluble in such product solutions evenin the presence of more than one mole of THF/NaCl.

    (iPr).sub.2 NMgCl+Na+0.5 PhCH═CH.sub.2 +(iPr).sub.2 NH+1.0 THF→(iPr).sub.2 NMgN(iPr).sub.2.THF+NaCl↓   (3)

One procedure for preparing magnesium bis-diisopropylamide in liquidhydrocarbon solvents containing no Lewis bases, such as THF, involvesthe use of preformed alkyllithium compounds, such as n-butyllithium,which require no THF, as reactants for diisopropylamidomagnesiumchloride in place of the "in-situ" directly formed lithiumdiisopropylamide of equation (2) which does require THF. Although thismethod will also produce a form of magnesium bis-diisopropylamide usefulin the subsequent preparation of the bimetallic diorganoamides of thisinvention, the process is wasteful of lithium metal since the formationof butyllithium requires the use of two equivalents of lithium metal permole of butyllithium formed, whereas only one equivalent of lithium isrequired in the process of equation (2).

Other variations to produce the magnesium bis-diorganoamides of theinvention are possible, including direct reaction of lithium andmagnesium metals with alkyl halides in hydrocarbon solvents in thepresence of limited amounts of Lewis bases such as tetrahydrofuran (THF)to form dialkylmagnesium compounds followed by addition of twoequivalents of diisopropylamine as shown in equation (4). ##STR2##

Again, however, reactions of this type are wasteful of expensive lithiummetal.

The hydrocarbon solutions of magnesium bis-diorganoamides produced bythe novel method of the invention [equations (1), (2) and (3) above],are highly stable and soluble at temperatures between 0° and 40° C. witha loss of less than 5 mole % in four weeks at 40°. Magnesiumbis-diisopropylamide produced by the invention is soluble to the extentof 1 mole per liter and higher as compared to the same product made inan ether-free solution from n-butyllithium which has a maximumsolubility of 0.7 molar at ambient or room temperatures.

Stable and soluble bimetallic lithium magnesium diorganoamidecompositions are prepared in liquid hydrocarbon solvents according tothe invention starting with magnesium bis-dialkylamides using a reactionscheme exemplified by the following equation for the preparation oflithium magnesium diisopropylamide compositions: ##STR3##

The reaction sequence shown in equation (5) can be used at all possiblevalues of x and y, so as to produce lithium magnesium diisopropylamidecompositions with x/y ratios varying from about 0.01 to 99. However, themagnesium bis-diisopropylamide required for this reaction must be madein a separate reactor if the ratio of x/y in the product is to be 0.5 orhigher because of the need to separate attendant LiCl by-product, inorder to avoid solubilization problems encountered later on in thelithium diisopropylamide preparation step. This is also described abovefor the preparation of magnesium bis-diisopropylamide made using lithiummetal [equation (2)].

The lithium metal reaction with diisopropylamine in equation (5) remainsvigorous at 0°-40° C. in the presence of even small amounts of magnesiumbis-diisopropylamide (MDA) in contradistinction to the reaction oflithium metal in the absence of MDA which proceeds well only at atemperature of 35° C. and above.

In equation (5), n (number of moles of THF) must be equal to or greaterthan x (mole fraction of lithium) in order to form x number of moles oflithium diisopropylamide.

If the desired ratio of x/y in the product is less than 0.5, then thereaction can be carried out directly in one pot usingdiisopropylamidomagnesium chloride [equation (1)], since, although atleast one mole of LiCl is formed for every 1.5 moles of lithium metalemployed, the THF requirement to produce 0.5 mole (or less) of LDA isless than half that needed to dissolve LiCl according to equation (6).##STR4## A preferred ratio of x/y in the product is less than 0.3 inorder to completely eliminate the presence of dissolved LiCl in theproduct. However, if the ratio of x/y in the product is greater than0.5, this process will unexpectedly yield a soluble bimetallicorganoamide composition containing dissolved lithium chloride, theamount of which depends upon x/y. Thus, for example, when x/y in theproduct is 2.0, and the required amount of THF is employed then all ofthe lithium chloride formed will be soluble. Other halide precursors tothe lithium salt can be prepared, such as diisopropylaminomagnesiumbromide.

Substitution of sodium for lithium as the chloride scavenger in theabove reaction, and as shown in equation (3) above, allows thepreparation of halide-free bimetallic organoamide products with x/yratios greater than 0.5, since the NaCl by-product formed remainsinsoluble even in the presence of at least one mole of THF as shown inequation (7). ##STR5## Values of n can be equal to 1 or higher withoutany danger of solubilizing the chloride salt.

Total substitution of sodium for lithium in equation (6) can also beeffected leading to stable, soluble, halide-free sodium magnesiumdiorganoamide compositions, Na_(x) Mg_(y) (NR₂)_(z).nTHF, even at x/yratios of 1 and higher, for example: ##STR6## Thus, a one pot reactioncan be utilized to produce the sodium magnesium diorganoamidecompositions at all x/y ratios directly from magnesium and sodium metals(2 step reaction), a distinct advantage over the comparable lithiumroute, where x/y in the product is limited to less than 0.5. As notedearlier [see equation (5)], lithium magnesium diorganoamide compositionsin which x/y is greater than 0.5 require the prior preparation (separatepot or reactor) of the chloride-free magnesium diorganoamide.

It should be noted that the sodium route requires the use of a fullequivalent of styrene per alkali metal atom, whereas the lithium routerequires the use of only a half of one equivalent of styrene per alkalimetal atom.

In place of diisopropylamine as the diorganoamide precursor, one maysubstitute a wide variety of diorganoamines. Generally, these are C₂-C₁₈ linear and branched dialkylamines such as, e.g., dimethylamine,diethylamine, di-n-propylamine, ethyl-n-propylamine, di-n-butylamine,ethyl-n-butylamine, di-n-hexylamine, n-butyl-n-hexylamine,di-n-octylamine, n-butyl-n-octylamine, di-2-ethylhexylamine,ethyl-2-ethylhexylamine, diisoamylamine, di-tert-butylamine,di-sec-butylamine, and so forth.

Along with and in admixture with the above-described diorganoamineprecursors, one may also utilize C₂ -C₁₈ linear and branchedmonoalkylamines, such as, e.g., methylamine, ethylamine, n-propylamine,isopropylamine, n-butylamine, isobutylamine, tert-butylamine,n-hexylamine, 2-ethylhexylamine, and the like. Thus, in the generalcomposition formula first written above, the organic groups representedin the formula by R and R' include C₂ to C₁₈ linear and branched groups.

Also contemplated are carbocyclic amines or mixtures thereof with theabove-mentioned acyclic amines such as, e.g., cyclopentylamine,dicyclopentylamine, cyclohexylamine, dicyclohexylamine,methyl-cyclohexylamine, isopropylcyclohexylamine, phenylamine (aniline),diphenylamine, methyl-phenylamine, ethyl-phenylamine, benzylamine,o-tolylamine, dibenzylamine, phenethylamine, methyl-p-tolylamine,p-t-butylphenylamine, and the like.

In addition, one may employ heteroalkyl or heterocycloalkyl orheteroaryl amines such as, e.g., hexamethyldisilazane, piperidine,pyrollidine, 2,2,6,6-tetramethylpiperidine, 8-aminoquinoline, pyrrole,3-methylaminopyridine, 2-methoxyethyl-methylamine,2-dimethylaminoethyl-methylamine, 2-trimethylsilylethyl-ethylamine,3-dimethylaminopropyl-ethylamine, 3-dimethylphosphinobutyl-methylamine,and the like.

The liquid hydrocarbon solvents useful in practicing this invention aretypically selected from aliphatic hydrocarbons containing 5 to 10 carbonatoms, alicyclic hydrocarbons containing 5 to 10 carbon atoms andaromatic hydrocarbons containing 6 to 10 carbon atoms. Exemplary ofthese liquid hydrocarbon solvents are pentane, n-hexane, n-heptane,mixed paraffinic hydrocarbons having boiling points below about 130° C.,cyclohexane, methylcyclohexane, benzene, toluene, ethylbenzene, xylene,cumene and so forth. The compositions of this invention produced by theprocess employing styrene or isoprene will include as part of thehydrocarbon system, the reduced alkali metal or electron carrier;ethylbenzene (EtBz) where styrene was used as the carrier and2-methyl-2-butene where isoprene is used. Other suitable electroncarriers may include butadiene, divinylbenzene and napthalene, forexample.

Contemplating the invention even more broadly, one may substitute othergroup VA elements for nitrogen in the organoamide portion of the metalorganoamide composition, such as, for example, phosphorus or arsenic.Thus, instead of organoamine precursors for such metal organoamidecompositions, one may employ organophosphine precursors for metalorganophosphide compositions. Thus, for example, one employsdimethylphosphine, diethylphosphine, tert-butylphosphine,phenylphosphine, cyclohexylphosphine, diisopropylphosphine,dioctylphosphine, and the like, in place of the corresponding amineslisted above to satisfy M^(c) RR' in the formula

    M.sub.x.sup.a M.sub.y.sup.b (M.sup.c RR').sub.z.nLB.mM.sup.d X

M^(a) metals in the above general formula M_(x) ^(a) M_(y) ^(b) (M^(c)RR')_(z).nLB.mM^(d) X are alkali metals of Group IA of the PeriodicTable, such as lithium, sodium, potassium, cesium, and rubidium, butmost preferably lithium and sodium. These metals can be employed in avariety of shapes and sizes, for example, as dispersions (in hydrocarbonmedia), sand, shot, chips or wire; but, for the most efficaceousresults, one generally employs the finely divided metals (less than 100micron particle size) dispersed in a hydrocarbon medium, such asheptane, cyclohexane, methylcyclohexane, or light mineral oil to keepthe surface of the metal particles protected during handling operations.

M^(b) metals in the above general formula M_(x) ^(a) M_(y) ^(b) (M^(c)RR')_(z).nLB.mM^(d) X are alkaline earth metals of Group IIA of thePeriodic Table, such as beryllium, magnesium, calcium, strontium, andbarium, and most preferably magnesium. Also contemplated, but lesspreferable, are other metals such as zinc, aluminum, and copper. Thealkaline earth metals, such as magnesium metal, can be employed in avariety of shapes and sizes, for example as powder, granules, chips, orturnings; but, for the most efficaceous results, powder is recommended.

The values of x, y, and z in the formula M_(x) ^(a) M_(y) ^(b) (M^(c)RR')_(z).nLB.mM^(d) X are related by the valence of the metal M^(b) inthe following way:

    x+y=1.0 and z=x+(y multiplied by the valence of metal M.sup.b)

Thus, for example, when metal M^(a) is lithium and the metal M^(b) ismagnesium, the value of z, representing the amount of organoamide (ororganophosphide) in the molecule will be equal to the value for x, i.e.,the mole fraction of lithium metal (per total moles of Li and Mg), plusthe mole fraction of magnesium times two (2.0).

In specific examples, the compounds Li₀.01 Mg₀.99 (NR₂)₁.99 and Li₀.99Mg₀.01 (NR₂)₁.01 represent opposite ends of the mole fraction range forLi and Mg. The maximum value for z is thus 2.0 and the minimum value forz is 1.0, and these values occur when only the pure compounds Mg(NR₂)₂and LiNR₂, respectively, are present.

The term LB in the formula M_(x) ^(a) M_(y) ^(b) (M^(c)RR')_(z).nLB.mM^(d) X stands for Lewis base, a polar, aprotic,non-reactive (to amide) organic compound which normally is assumed toassociate with the metal organoamide in an amount equal to n moles permole of metal organoamide, which value is generally less than four.Lewis base types contemplated in this invention are: acyclic and cyclicethers such as dimethyl ether, diethyl ether, di-n-butylether,methyl-tert-butylether, tetrahydrofuran, 2-methyltetrahydrofuran,tetrahydropyran, 2-methyltetrahydropyran, 1,2-dimethoxyethane,1,4-dioxane, diethylene glycol diethyl ether, and the like. Alsocontemplated are acyclic and cyclic tertiary amines such astrimethylamine, triethylamine, tri-n-butylamine,dimethyl-cyclohexylamine, N-methylpyrrolidine, N-methylpiperidine,N-methylmorpholine, N,N,N',N'-tetramethylethylenediamine,2-dimethylaminoethyl-ethyl ether, and the like. Also contemplated areamines identical to those employed in the preparation of the metalorganoamide compositions themselves (see above).

Also contemplated are hydrocarbon-soluble compounds of the type shownabove which also contain complexed metal halides such as lithiumchloride and bromide, generally represented by the formula M_(x) ^(a)M_(y) ^(b) (M^(c) RR')_(z).nLB.mM^(d) X, where M^(d) is an alkali metal,specifically lithium, X is halogen, generally chlorine, n is a numberwhich when multiplied by z is greater than one and less than four, and mis a number between one and two.

The process for preparing such compositions may begin with theconversion of magnesium metal to a mono- or dialkylamidomagnesium halideas shown in equation 1 and described above, followed by admixture withlithium metal (finely divided) and reaction thereof with mono- ordialkylamine in the presence of styrene and sufficient LB (preferablytetrahydrofuran) to dissolve the attendant by-product lithium halide(generally chloride or bromide). As mentioned earlier, the amount of LB(THF) required to completely dissolve this lithium halide is generallyequal to about two molar equivalents per mole of halide. Generally, thevalue of m in the above equation will not be greater than two.

Obviously, lithium halide salts such as lithium chloride or lithiumbromide (anhydrous) may be added to the compositions of general formulaM_(x) ^(a) M_(y) ^(b) (M^(c) RR')_(z).nLB, where n is sufficiently high,to dissolve them therein and to form the novel compositions of thisinvention. The value for x in the above general formula may be zero,whereupon the products of the invention are hydrocarbon solutions ofmagnesium bis-monoalkylamides and magnesium bis-dialkylamides containingdissolved (complexed) lithium halides. In like manner, the value for yin the above general formula may be zero, whereupon the products of theinvention are hydrocarbon solutions of lithium monoalkylamide andlithium dialkylamides containing dissolved (complexed) lithium halides.The lithium halides alone have no solubility in hydrocarbon solventscontaining limited amounts of Lewis base although lithium bromide,alone, is soluble in pure THF to the extent of approximately one-thirdof a mole per mole of THF. The following formulas describe some of theprocesses involved in the preparation of these compositions.

A. Preparation of LiMg(NR₂)₃ nTHF.mLiX ##STR7## B. Preparation ofMg(NR₂).nTHF.mLiX ##STR8## C. Preparation of LiNR₂.nTHF.mLiX

    LiN(iPr).sub.2 +LiBr↓+2.5 THF→LiN(iPr).sub.2.LiBr.2.5 THF (15) solution in cyclohexane

    Solution concentration=1.0M each in LiN(iPr).sub.2 and LiBr.

Group IIA (alkaline earth) metal organoamides, such as magnesiumbis-diisopropylamide (MDA), can be prepared in a number of ways asdescribed earlier. One key method involves (a) the reaction of magnesiummetal with a mixture of n-butyl chloride and diisopropylamine inhydrocarbon solvent at reflux temperatures (the reflux temperature dropsconstantly during the addition due to release of n-butane) over a fourhour period to form a slurry of diisopropylamidomagnesium chloride; (b)addition of lithium metal (sand or dispersion) followed by a mixture ofdiisopropylamine (25% of amine is in pot to start), tetrahydrofuran andstyrene, first at 35°-40° (initiation of reaction), then at 30°±5° C.over a 2-3 hour period; and (c) filtration to give a clear solution ofthe product. Sodium dispersion can be used in place of the lithium metalin step (b). The initial reaction temperature of step (a) is generallythe boiling point of the hydrocarbon solvent in which the reaction istaking place. Hydrocarbon solvents such as heptane, cyclohexane, orethylbenzene are employed. As reaction progresses during the addition ofalkyl halide and amine to the magnesium metal, the reflux temperaturedrops due to evolution of butane. Thus, for example, when heptane is thehydrocarbon solvent, the reaction temperature will drop from an initialvalue of about 98° C. to a value of about 60° C. After addition ofreactants is complete, the mixture is stirred and kept at 60° C. for anadditional 2-3 hours to complete the reaction. The resultingdiisopropylamidomagnesium chloride is insoluble in the reaction medium.In step (b), lithium diisopropylamide is formed as an intermediate,which then reacts with the diisopropylamidomagnesium chloride to givethe desired magnesium bis-diisopropylamide in solution and a precipitateof lithium chloride. It is useful to initiate the lithium metal reactionwith styrene and diisopropylamine generally in the presence of a maximumof 0.5 molar equivalents of THF per mole of lithium and preferably lessthan 0.4, but more than 0.2 molar equivalents of THF/mole Li, mostpreferably between 0.3 and 0.4 molar equivalents of THF/mole Li attemperatures of about 40° C.; and then to carry out the remainder of theaddition and post-addition reaction at somewhat lower temperatures inorder to minimize side reactions. An overall reaction range is 0°-50° C.with a preferred range of 20°-40° C. and a most preferred range of35°-40° C. The use of limited THF as described above results in theformation of halide-free solutions of the desired product. Shouldlithium-halide-containing solutions of MDA be desired, at least 0.5molar equivalents of THF, and preferably at least 1-2 molar equivalentsof THF per mole of lithium should be employed. Alternatively,n-butyllithium instead of lithium metal may first be reacted withdiisopropylamidomagnesium halide, and the resulting n-butylmagnesiumdiisopropylamide reacted further with diisopropylamine in the presenceof the desired quantity of THF to give either halide-free orhalide-containing product. Overall, processing times under theseconditions are generally less than 12 hours, with a most preferredperiod of four hours and under for each step of the reaction.

If an ether-free halide-free hydrocarbon solution of magnesiumbis-diisopropylamide (MDA) is desired, then either a dialkylmagnesium,such as n-butyl-sec-butylmagnesium, is reacted directly with 2 molarequivalents of diisopropylamine; or the product of reaction (a) above isreacted first with n-butyllithium, then with diisopropylamine to convertthe diisopropylamidomagnesium chloride to magnesium bis-diisopropylamideand the by-product lithium chloride filtered off. Such etherfreesolutions of MDA show a limited solubility for the product (MDA), themaximum solubility being about 0.7-0.8 moles/liter at temperatures of0°-30° C. Addition of 1 and 2 moles of THF, respectively, per mole ofMDA allows for the preparation of MDA in hydrocarbon solutions inconcentrations of at least 1 and 2 moles MDA per liter of solution,respectively. In any case, the use of a dialkylmagnesium compound toprepare MDA is less economical than the two step magnesium metallithiummetal route described earlier.

Variation of the dialkylamine employed in reaction (a) above in certaincases results in the direct formation of the desired magnesiumbis-diorganoamide. Thus, for example, utilization of >2 molarequivalents of di-n-hexylamine in place of diisopropylamine in thedirect reaction of magnesium metal with n-butyl chloride gives a viscoushydrocarbon solution of magnesium bis-di-n-hexylamide and insolubleMgCl₂. It is believed that the longer chain (C₅ and higher)dialkylamines yield somewhat more soluble intermediatedialkylamidomagnesium chlorides which allow the reaction to proceedfurther to the desired bis-dialkylamides, whereas the lower chain (<C₅)dialkylamines do not.

The above-described Group IIA metal bis-organoamides, such as magnesiumbis-diisopropylamide, can be utilized further to prepare thehydrocarbon-soluble bimetallic Group IA/IIA metal organoamides of thepresent invention.

However, in the presence of 1.5±0.5 moles of tetrahydrofuran per mole oforganoamide, the soluble amide concentration of such Li_(x) Mg_(y)(N(iPr)₂)_(z) compositions could be increased to 2.0 molar and above,and these solutions were stable to further precipitation with time. Ithas now been found possible to economically prepare suchhydrocarbon-soluble solutions of Li_(x) Mg_(y) (NR₂)_(z) in which x+y=1and z=x+2y, via novel routes.

One such economical route is useful if the resultant x/y ratio in theLi_(x) Mg_(y) (NR₂)_(z) composition is held below about 0.3. Forexample, diisopropylamidomagnesium chloride is first prepared as ahydrocarbon slurry as described above from magnesium metal, n-butylchloride, and diisopropylamine. Next, lithium metal in the form of adispersion of finely divided particles [1.3 moles Li/mole(iPr2N)MgCl] isadded to the slurry held at about 40° C. To the slurry is then added,dropwise, a solution of styrene (˜0.5 mole/mole Li), diisopropylamine(˜1 mole/mole Li) and tetrahydrofuran (˜0.3 mole/mole Li) to form LDA,keeping the reaction temperature generally in the range of 20°-40° C.,and most preferably in the range of 30°-35° C. The resultant solution isfiltered away from the by-product LiCl salt which is totally insolublein the medium. The ratio of THF to LiCl in the final product compositionis thus held well below 0.5, and no solubilization of LiCl by the THFoccurs at the THF/LDA (1.0±0.2) ratios necessary to promote the LDAformation.

However, when x/y ratios in the Li_(x) Mg_(y) (NR₂)_(z) product aboveabout 0.3 are sought, preformed MDA, free of by-product LiCl, should beemployed in place of diisopropylamidomagnesium chloride, in order toavoid solubilization of by-product LiCl by the greater amount of THFrequired to promote the formation of the larger proportionate amount (toMDA) of LDA. The use of preformed MDA in this case is a two pot reactionand therefore is more expensive than the one pot synthesis describedabove. As mentioned earlier, the THF requirement to obtain higher than a1.5 molar amide concentration in hydrocarbon solutions is about 1.0 moleTHF per mole of amide. Thus, solubility of the compositions Li_(x)Mg_(y) (NR₂)_(z) in hydrocarbons, where x/y is <0.5, will be limited bythe smaller amount of THF utilized in the diisopropylamidomagnesiumchloride route to prevent LiCl solubilization. The halide-free MDA routeto Li_(x) Mg_(y) (NR₂)_(z) has no such limitation, and halide-freeorganoamide concentrations of these compositions of 2.0M and higher arereadily achieved. As described earlier, the limitation on x/y ratio canbe eliminated by the use of sodium metal in place of lithium in thepreparation of precursor diisopropylamidomagnesium chloride, since NaClby-product is not solubilized by THF/LDA levels of 1.0 or higher. TheMg/Na/Li ternary metal route thus allows for an inexpensive one potsynthesis of Li_(x) Mg_(y) (NR₂)_(z) in hydrocarbon solutions at amideconcentrations of 2.0M and above. Obviously, ternary metallic amidecomplexes can be made by variation of the proportions of the threemetals involved.

When the x/y ratio in the product Li_(x) Mg_(y) (NR₂)_(z) issufficiently high (>10), then the source of the MDA used in itspreparation no longer contributes as significantly to the overall costof the product. Thus, a Li₀.95 Mg₀.05 (N(iPr)₂)₁.05 composition can bereadily prepared by first reacting n-butyl-sec-butylmagnesium in heptane(DBM, Lithco) with 2 molar equivalents of diisopropylamine, then addinglithium metal (sand or dispersion) followed by the dropwise addition ofa mixed solution of THF, styrene, and diisopropylamine over a three hourperiod at 30°-35° C., and then a post-addition reaction period of onehour yielding a clear light-colored solution of the desired productafter filtration. Preformed halide-free MDA solutions or an MDA+NaClslurry which are less costly than DBM may also be used. Although lithiummetal is employed as the most economical raw material for the formationof lithium diisopropylamide, it is understood that one may also employorganolithium compounds such as n-butyllithium, methyllithium,2-ethylhexyllithium, ethyllithium, phenyllithium, etc., in the reactionwith diisopropylamine, although they are more expensive to use than themetal.

Such Li_(x) Mg_(y) (NR₂)_(z) compositions in hydrocarbon solutioncontaining somewhat more than 1 mole of THF/mole amide, where x/y=19 oreven higher, have now been prepared and unexpectedly have been found tobe significantly more resistant to thermal decomposition than comparableLiN(iPr)₂ solutions containing ≦1 mole of THF/mole amide.

Surprisingly LiN(i-Pr)₂ hydrocarbon solutions containing about 1.5 molesTHF/mole amide also possess an

improved stability as compared to comparable LiN(i-Pr)₂ solutionscontaining one or less moles of THF/mole amide. It had been earlierreported in U.S. Pat. No. 4,595,779 that high levels of THF (2-6 molesTHF/mole of amide) contributed to an escalating rate of decomposition(see cols. 3 and 4, Table I, sample numbers C and D; also see col. 4,lines 45 to 48). On the other hand it was shown in the same reference(col. 4, lines 48-61) that significantly lower decomposition rates wereevident at THF/amide ratios of 1 and below. At THF/amide ratios of about0.5, LiN(i-Pr)₂ product precipitated from solution (col. 4, lines 62 to66) at 0° and 20° C. Thus, a useful range of THF/amide of 0.5 to 1.1 wasclaimed in this patent (see claim 22). Little or no information waspresented to cover the intermediate range of 1.1 to 1.9 moles ofTHF/amide, except to show that there was no significant differencebetween ratios of 1.1 and 9.0 (Table I, F to J). It has now beenestablished that THF/amide ratios in the range of 1.1 and 1.9, and morepreferably in the range of 1.2 to 1.6 lead to a more stable (boththermal and precipitation) LiN(i-Pr)₂ product solution. For example, a2.5 molar solution of LiN(i-Pr)₂ in heptane with an initial THF/amideratio of 1.38 and also containing 7.7 mole percent free diisopropylamine(stabilizer) decomposed at a rate of 0.6% per day at 40° C. This can becompared to a loss of 1.16% per day (see entry sample number 0 in TableI of U.S. Pat. No. 4,595,779) for a comparable solution.

The major decomposition of LDA at THF/LDA ratios of 1.0 or less wasfound to be as follows: ##STR9## For example, at a THF/LDA ratio of 0.95the loss of LiN(i-Pr)₂ by the above mechanism constitutes 100% of thetotal loss observed. Whereas, at a THF/LDA ratio of 1.38 the percentageloss by the above shown route was found to be only 35%. Thus, othermodes of decomposition, perhaps involving metallation of THF andethylbenzene, become the major routes to loss of product. This couldreadily account for the change (decreased rate) of loss of LiN(i-Pr)₂,since the above mechanism requires the consumption of two molarequivalents of LiN(i-Pr)₂ for every mole of product decomposed, whilethe other suggested moles of decomposition, i.e., metallation requireonly one.

Thermal stability testing of LDA and LDA containing 5 mole % MDA (LDA-1)in solution in a hydrocarbon solvent were carried out to determine thetrue rates of decomposition at three different temperatures. Details ofthis testing are summarized in the Table. Detection and quantitation ofthe lithiated imine formed on thermal decomposition as well as thepresence of lithium hydride was verified.

Thermal stability at 0° and below

Thermal stability testing at 0° C. indicated both LDA and LDA-1 (LDAcontaining 5 mole % MDA), to be stable for at least 70 days. No imineand/or precipitation of hydride was detected in any of these samples.The solubility of both LDA and LDA-1 is reduced at -20° C.±5° andcrystalline solid product drops out, but which redissolved easily atroom temperature in the case of LDA-1, whereas in the case of LDA it ishard to redissolve the solid crystals without shaking for a long time atroom temperature. LDA-1 samples showed no crystallization(precipitation) at -20° C. when the THF to LDA mole ratio was 1.2 andhigher.

Thermal stability at 15° C.±0.5°

LDA-1 samples (containing ˜5 mole % MDA) showed improved thermalstability at milder temperatures (15° C.±0.5° C.) as compared to LDA. Nodecomposition or precipitation or imine formation were detected in LDA-1samples (see Examples 3, 5 and 6) after testing for 70 days at 15° C.LDA (with no MDA) degraded at an average rate of 0.11 mole % per dayduring the same period (see Example 1). The loss was verified bydetection of imine. All LDA samples became cloudy in appearance in oneweek's time. It was also noted that LDA solutions turned even moreturbid at somewhat higher temperatures (20° C.±5° C.) whereas LDA-1solutions remained clear.

Thermal stability at 40° C.±0.5°

Thermal stability testing at 40° C. indicated that after 14 days, LDA(see Example 4; 1.36 mole % loss per day) degraded six times morerapidly than LDA-1 (Example 5; 0.22 mole % per day). As expected, after28 days at 40° C., the degradation rate of LDA (Example 1) slowedsomewhat to 1.25 mole % per day but was still about three times higherthan that of LDA-1 (Example 3; 0.45 mole % per day). The loss of activeproduct due to precipitation from LDA-1 samples (Examples 3 and 6) isbelieved to be caused by an insufficient amount of THF and freediisopropylamine in these samples. As can be seen from Example 5, theaverage rate of decomposition was lower in Example 5 as compared toExamples 3 and 6 because of the above-mentioned condition.

Comparison of imine formation due to decomposition indicated LDA-1(Example 6; 0.10 mole imine/kg solution) to be three times more stablethan LDA (Examples 1 and 4; 0.33 and 0.32 mole imine/kg respectively).

Thus, the above results and data indicates that LDA-1 (containing about5 mole % MDA) is significantly thermally more stable than LDA at anytemperature between -20° C. to 40° C., especially between 15° C. and 40°C.

                                      TABLE                                       __________________________________________________________________________    Thermal Stability Comparison of LDA Vs. LDA Containing                        ˜5 Mole % MDA (LDA-1) in Limited THF/Heptane Solvents at Various        Temperatures                                                                                                        Average Mole % Loss of Activity         Example                                                                            Product                                                                            Initial.sup.(a) Active                                                                MDA Conc.                                                                            THF/LDA                                                                             Free.sup.(b) Amine                                                                   Per Day at Various Temperatures         No.  Name Amide (M/kg)                                                                          (M/Kg) Mole Ratio                                                                          Mole % 0 C. + 3.sup.(c)                                                                    15 C. + 0.5.sup.(c)                                                                  40 C.                      __________________________________________________________________________                                                       + 0.5                      1    LDA  2.58    0.0    1.02  7.5    0.0    0.11  1.25.sup.(d)               2    LDA.sup.(f)                                                                        2.76    0.0    0.89  5.4    --    --     1.16.sup.(d)               3    LDA-1                                                                              2.65    0.126  1.05  11.0   0.0   0.0    0.45.sup.(d)(g)            4    LDA  2.53    0.0    1.05  17.5   --    --     1.36.sup. (e)              5    LDA-1                                                                              2.44    0.121  1.13  20.0   0.0   0.0    0.22.sup.(e)               6    LDA-1                                                                              2.58    0.135  1.03  9.00   0.0   0.0    0.47.sup.(e)(g)            __________________________________________________________________________     .sup.(a) W/E titration  corroborated by GLC analysis                          .sup.(b) Free amine is diisopropylamine                                       .sup.(c) Mole % loss per day over a period of 70 days                         .sup.(d) Mole % loss per day over a period of 28 days                         .sup.(e) Mole % loss per day over a period of 14 days                         .sup.(f) Data taken from Table 1, U.S. Pat. No. 4,595,779; Examples 1 and     4 were similarly prepared                                                     .sup.(g) Precipitation of some magnesium noted at 40 C. after 14 days         which caused higher rate of loss of total active amide.                       Note:                                                                         Samples for Example Nos. 3, 5 and 6 (above) were prepared according to th     procedure given in Example III B.1.                                      

The following examples further illustrate the invention. Unlessindicated otherwise temperatures are in degrees C., percentages ofreactants are in weight percent. All glassware was baked in an oven(150° C.) overnight, assembled, and purged until cool with argon. Aninert argon atmosphere was maintained throughout reaction, filtration,and packaging. The metal amide concentration and compositions weredetermined by Total Base, Carbon metal bond assay (Watson Easthamtitration and/or NMR), and Magnesium titration. The lithium andmagnesium ratio is confirmed by Atomic Absorption Spectroscopy. Thechloride content of solution was determined by Mohr titration. Alllithium metal used contained 0.7% to 1.25% sodium.

EXPERIMENTAL Example I Preparation of Magnesium Bis-diisopropylamide(MDA) A. Ether-Free Hydrocarbon Soluble MDA 1. Ether-free H.C. solubleMDA from dialkylmagnesium

One hundred sixty-five gms n-butyl-, sec-butyl magnesium (DBM) (20.8 wt% solution in n-heptane, 1.04 molar, 0.74 gm/ml density), was chargedinto a reaction flask under argon atmosphere. Thirty-four mls (0.2428moles) of diisopropylamine was then added dropwise through an additionfunnel to DBM under good agitation. Reaction temperature was maintainedbetween 25° C. and 59° C. (reflux). Product solution was then sampledfor NMR and G.C. analysis to verify completion of the reaction. Thereaction solution was then reacted further with an additional 34 mls(0.2428 moles) of diisopropylamine added between 25° C. and 53° C.(reflux) to form magnesium bis-diisopropylamide. The final solutionproduct was sampled for NMR and G.C. analysis. The solution was found tocontain 2.55 wt % Mg and was 0.80 molar in MDA. It contained 0.093 molesfree amine/mole of MDA, yield 100%. The solution was stable toprecipitation at room temperature and above, but some crystallizationoccurred at 0° to give a 0.7M solution.

2. Ether-free H.C. soluble MDA from Mg metal/n-BuLi route

Magnesium metal chips (12.0 gms, 0.494 mole), 0.20 gms iodine crystals,and 400 mls of n-heptane were charged into a glass reactor under argonatmosphere. The metal slurry was then heated to reflux (98° C.) for 60minutes for activation of metal. n-Butylchloride (52 mls, 0.50 mole) and70 mls of diisopropylamine were mixed in an addition funnel and addeddropwise to the metal slurry at reflux temperature. Within a few minutesbutane started refluxing, and reflux temperature dropped between 55° C.to 60° C. The reaction was completed at 55° C. to 60° C. in about threehours, and all metal chips had been converted into a fine white solidproduct in n-heptane solvent. No soluble magnesium was found in solvent.To this slurry 480 mls (0.48 mole) n-butyl lithium in n-heptane wasadded at 25-30° C. in about 30 to 40 minutes under good agitation,followed by addition of 70 mls (0.5 mole) of diisopropylamine. Stirringwas continued for an additional 60 minutes before it was filtered toremove solids. About 890 mls of clear filtrate was obtained. The finalsolution (filtrate) was analyzed and found to contain 1.77 wt % Mg (0.48molar MDA) and 0.143 mole free amine/mole MDA. Yield=90% concentrationto 0.7M gave a highly stable solution between -20° and 40° C. (no lossfor several months). Similarly, MDA in cyclohexane was prepared wheren-BuLi in cyclohexane was used. The final filtrate was concentrated to0.7 molar concentration by distillation of solvent, and it was found tobe highly stable between 0° and 30° C. for more than 60 days.

3. Ether-free H.C. soluble magnesium bis-di-n-hexylamide from Mgmetal/di-n-hexylamine reaction

Magnesium metal chips (12.5 gm, 0.51 mole) 250 mls cyclohexane and 0.25gm iodine crystals were charged first in one liter reaction flask andheated to reflux (80° C.) for 60 minutes for metal activation.n-Butylchloride (52 mls, 0.495 mole) was then added gradually to thereaction flask at reflux temperature, but no significant reaction withmetal occurred, and therefore di-n-hexylamine (120 mls, 0.514 mole) wasadded to the reaction slurry. Reaction of metal with reagents wasvigorous at reflux. Reflux temperature was seen dropping to 50° C.during this reaction. The reaction was continued for about three hoursat reflux temperature. Almost all magnesium metal chips disappeared, andreaction slurry containing fine solids turned to a very viscous and notfilterable condition. Next, 50 mls of cyclohexane and 58.6 mls ofdi-n-hexylamine was added gradually to thin the reaction slurry beforebeing filtered. The final slurry was filtered well and yielded about 400mls of clear yellow solution containing 0.6 molar Mg, 1.12 molar activeamide, and traces of halide. Excess (free) amine was 1 mole per mole ofMDA. Yield=90%. Solution was highly stable for months at 0° C. to roomtemperature.

B. Hydrocarbon Soluble MDA Complexed with Limited Amount of Ether(THF) 1. H.C. soluble MDA.nTHF from Mg metal/Li metal route

Magnesium metal chips (12.95 gm, 0.532 mole), 300 mls of n-heptane, and0.25 gm pure iodine crystals were charged into the reaction flask underargon atmosphere and then heated to reflux temperature (98° C.±1.0°) forabout an hour for metal activation. n-BuCl, 50 mls (0.478 mole) and 67.5mls (0.48 mole), of diisopropylamine were mixed in an addition funneland then added dropwise to the metal slurry in 90 minutes at refluxtemperature (60°-98° C.). Reflux temperature was dropped constantlyduring addition of reactants due to release of butane. Reaction wascontinued for three more hours after completion of addition ofreactants. The reaction slurry containing white fine solids was thencooled down to ≦40° C. To this slurry 3.20 gm (0.461 mole) of lithiummetal sand was added at 35° C.±5° C., followed by dropwise addition of amixture of 70 mls (0.5 mole) diisopropylamine, 13 mls (0.16 mole) THFand 27 mls (0.237 mole) styrene through an addition funnel, first at 38°C. for about 10 minutes and then at 25° C.±5° C. in two to three hours.The reaction slurry was then left overnight at 20° C.±5° C. undermoderate stirring and argon atmosphere. The next morning hardly anylithium metal sand was found unreacted (nothing floating). The reactionslurry was then filtered to remove solid and a clear light yellowishsolution filtrate was obtained. The product was analyzed: Wt % Mg=2.94,THF/MDA--0.33 MDA=0.91M, excess amine=0.1 mole/mole MDA, yield--90%.Similarly, MDA in cyclohexane was prepared.

2. H.C. soluble MDA.nTHF from dialkylmagnesium

The MDA solution, in ether-free hydrocarbon solvent made from thereaction of DBM with diisopropylamine as described earlier in I-A-1, wasconcentrated to 1.09 molar MDA from 0.70 molar by distillation ofsolvent under reduced pressure at ≦25° C. The concentrated 1.09 molarsolution of MDA on standing produced some solid (precipitation) MDA,leaving 0.7 molar solution. The precipitated solids were found to besoluble in its mother solution at higher temperature (>25° C.). Addingone mole THF per mole of magnesium to this solution, no solidprecipitation occurred on cooling to below 0° C. over one week. Inanother test it was found that the 2 mole THF per mole of MDA produceshighly concentrated 2.2 molar MDA in n-heptane, excess amine=0.05mole/mole MDA, THF/MDA=2.0, yield=100% which was also found to be highlystable between 0° and 40° C. At 40° C. in about 4-5 days, solutionturned to dark reddish brown, but was clear.

3. H.C. soluble MDA.nTHF from Mg metal/Na metal route

Magnesium metal (12.50 gms, 0.51 mole), 0.3 gm iodine crystals, and 200mls of n-heptane were charged into a one liter reaction flask underargon atmosphere. The metal slurry was then heated to reflux (98°C.±1.0° C.) for 60 minutes to activate the surface of the metal.

The mixture of 74 mls (0.52 mole) diisopropylamine and 53 mls (0.51mole) of n-butyl chloride was added dropwise to the metal slurry atreflux temperature in about two hours. The reflux temperature dropped to60°-63° C. due to the release of butane from the reaction. The reactionslurry was allowed to stir at reflux temperature for three hours tocomplete the reaction. The slurry was left overnight under slow stirringand argon atmosphere at NTP. The next morning 10.35 gm (0.45 mole) Nametal was added to the reaction slurry at room temperature (22° C.). Theslurry was heated to 38° C. and then reacted with a dropwise addition ofa mixture of 50.8 mls (0.435 mole) styrene, 11.0 mls (0.135 moles) THF,and 70 mls (0.5 mole) DIPA. The reaction temperature was dropped bycooling bath to 30° C.±2° C. after 10 minutes of reaction at 38° C. Themix reagents were added to the pot in about 2.5 hours. The reactionslurry was left overnight under slow stirring and argon atmosphere. Thenext day the slurry was filtered to remove solids and a clear yellowsolution (filtrate) was obtained. The clear solution product wasanalyzed and found to contain 3.20 wt % Mg (1.0M MDA), THF/MDA=0.31,excess amine=0.03 mole/mole MDA, yield=97%. Solution was stable between0° and 40° C.

Example II Preparation of Lithium Magnesium Alkylamide Complex CompoundsA. Ether-free Hydrocarbon Soluble Li_(x) Mg_(y) (NR₂)_(z) ComplexCompounds from Lithium and Magnesium Alkyls

1. Li(NR₂): n-Butyllithium in cyclohexane (40 mls, 0.04 mole) wasreacted with 12.5 mls (0.089 mole) diisopropylamine at <10° C. Thetemperature of the reaction mixture was then raised to 30° C. The solidLDA formation during low temperature reaction did not solubilize at30°-35° C.

2. Li₀.33 Mg₀.67 (NR₂)₁.67 : Ether-free cyclohexane soluble magnesiumbis-diisopropylamide (75 mls, 0.0375 moles) was first charged into areaction flask under argon atmosphere, followed by adding to it 3.0 mls(0.02143 mole) diisopropylamine. This solution was then reacted withdropwise addition of 9.0 mls (0.018 mole) n-butyllithium in cyclohexaneat low temperature (10° C.) using cooling bath. Release of free butaneduring addition of butyllithium was seen. Clear solution product,without forming any solid, was obtained. The reaction product assolution remained clear for a couple of days. The analysis of thesolution showed the presence of Li=0.21M, Mg=0.43M, Amide=1.07M, excess(free) amine=0.03 moles/mole Amide.

3. Li₀.50 Mg₀.50 (NR₂)₁.5 : The above experiment (2) was repeated asdescribed above, and then 3.0 mls (0.02143 mole) of additionaldiisopropylamine was added first followed by the addition of 9.0 mls(0.018 mole) of n-butyllithium at <1.0° C. The reaction mixture wasstirred well at low temperature and then at room temperature. No solidwas formed. The clean solution product was found to be stable between 0°C. and room temperature for at least one day. The analysis of theproduct showed the presence of Li=0.36M, Mg=0.38M, Amide=1.12M, excess(free) amine=0.06 mole/mole Amide.

4. Li₁.67 Mg₀.33 (NR₂)₁.33 : The above experiment (3) was repeated asdescribed above, and then 6 mls (0.04285 mole) of diisopropylamine wasadded to it followed by adding 18 mls (0.036 moles) of n-butyllithium at<10° C. under good agitation. The reaction mixture continued stirring atroom temperature for some time. The clear solution without forming anysolid at room temperature was obtained. The solution product did formsolid (precipitation) at <10° C. on cooling for some time. The analysisof this product showed the presence of Li=0.58M, Mg=0.305, Amide=1.20M,excess (free) amine=0.09 mole/mole Amide.

5. Stable and Soluble Lin₀.67 Mg₀.33 (NR₂)₁.33 in H.C. Solvent UsingLimited THF: Ninety grams of above prepared solution (4) was chargedinto a vacuum flask and then concentrated by distilling solvent atreduced pressure until 54.0 gm weight was attained. The concentratedsolution turned hazy and, subsequently, turbid in a few minutes at roomtemperature.

The concentrated solution containing fine solids was turned into a thickslurry on cooling to 10° C. To this slurry 12 mls (0.146 mole) THF wasadded gradually under good agitation to obtain clean and clear solution.The clear solution product did not produce any solid between 0° C. androom temperature for about a week. The final solution had 1.86M activeamide concentration. The analysis showed the presence of Li=0.91M,Mg=0.47M, Amide=1.86M, excess (free) amine=0.09 mole/mole of Amide.

B. Preparation of Soluble Li_(x) Mg_(y) (NR₂)_(z).nTHF Complex in H.C.Solvent by Using Lithium Metal Route

1. Li₀.23 Mg₀.77 (NR_(b) 2)₁.77.0.35THF in n-Heptane: Magnesium metalpowder (12.0 gm, 0.493 mole), 0.25 gm iodine crystals, and about 560 mlsof n-heptane were charged into a glass reactor under argon atmosphere.The metal slurry was heated to reflux temperature (98° C.±1.0) for 60minutes for activation of metal. n-Butylchloride (51 mls, 0.49 mole) anddiisopropylamine (70 mls, 0.5 mole) were mixed in an addition funnel,then added dropwise to the metal slurry at reflux temperature (98°-60°C.) over a period of 90 minutes. The reaction was completed at reflux inan additional two hours of stirring. The reaction slurry was changedinto fine whitegray solids containing product in n-heptane. Next, theslurry was allowed to cool to around 40° C. by using outside coolingbath. To this slurry 4.7 gm (0.677 mole) of lithium metal was added.Next, 38 mls (0.332 mole) styrene, 100 mls (0.714 mole)diisopropylamine, and 17 mls (0.20 mole) THF were mixed in an additionfunnel and then added dropwise to the reaction flask at 40° C. for 10-12minutes to initiate the reaction of lithium metal with reagents. Thereaction temperature was then maintained at 30° C.±5.0° C. by using acooling bath for the remaining 2.5 hours of addition of reagents to thereaction flask. The reaction slurry was allowed to remain overnightunder slow stirring at normal temperature (25° C.±5° C.). The next daythe slurry was filtered to remove solids and recover clear yellow colorfiltrate. The volume of recovered filtrate was about 825 mls. Theanalysis of the solution product showed the presence of Li=0.156M,Mg=0.522M, Amide=1.20M, THF/Amide=0.20, yield=86%.

2. Li₀.34 Mg₀.65 (NR₂)₁.64.1.62THF in n-Heptane: Magnesiumbis-diisopropylamide in n-heptane (500 mls, 0.75 molar) was firstcharged into a one liter reaction flask followed by 2.1 gm (0.3 mole)lithium metal sand. To this slurry a mixture of 75 mls (0.9 mole) THF,15.75 mls (0.13 mole) styrene, and 39 mls (0.28 mole) ofdiisopropylamine were added dropwise through an addition funnel at 35°C. for 5-10 minutes and then at 30° C. over a period of two hours. Thereaction slurry continued to agitate for an additional two hours at roomtemperature. Next, the reaction slurry containing solid was filtered toremove solids and recovered approximately 575 mls of filtrate. Thesolution product was clear and had lemon yellow color. The analysis ofthis product showed the presence of Li=0.34M, Mg=0.65M, Amide=1.64M,THF/Amide=0.99, yield=86%.

3. Li₀.67 Mg₀.33 (NR₂)₁.33.1.21THF in n-Heptane Solvent: Magnesiumbis-diisopropylamide in n-heptane (333 mls, 0.70 molar) was firstcharged into a one liter flask followed by charging 4.2 gm (0.605 mole)lithium metal dispersion in n-heptane. Next, to this slurry a mixture of76 mls (0.90 mole) THF, 28 mls (0.245 mole) styrene, and 78.6 mls (0.561mole) of diisopropylamine was added dropwise through an addition funnelat 35° C., first for an initial 10 minutes and then at 30° C. over aperiod of two hours. The reaction slurry was allowed to agitate for twoadditional hours at room temperature. The reaction slurry was thenfiltered to remove solids and recovered approximately 600 mls offiltrate having light lemon yellow color. The analysis of the productshowed the presence of Li=0.84M, Mg=0.38M, Amide=1.59M, THF/Amide=0.91,yield=90%.

4. Li₀.833 Mg₀.167 (NR₂)₁.167.1.06THF in n-Heptane: Magnesiumbis-diisopropylamides in n-heptane (166 mls, 0.75 molar) was firstcharged into a one liter reaction flask followed by adding 6.3 gm (0.908mole) lithium metal and 70 mls of n-heptane. Next, to this slurry amixture of 76.0 mls (0.90 mole) THF, 47 mls (0.41 mole) styrene, and 118mls (0.84 mole) diisopropylamine was added dropwise through an additionfunnel at 35° C. for 10 minutes to initiate the reaction, and then thereaction continued at 30° C. over a period of two hours. The reactionslurry was agitated for an additional two hours at room temperaturebefore being filtered to remove solids. The resulting solution product(filtrate) was gold yellow in color and clear. The analysis of theproduct showed the presence of Li=1.38M, Mg=0.27M, Amide=1.89M,THF/Amide=0.91, yield=92%.

Example III Preparation of Soluble Lithium Diisopropylamide:THF Complexin H.C. Solvent in the Presence of A Small Amount of MDA (Made by UsingDialkyl Mg/Mg Metal) A. Preparation of Hydrocarbon Soluble LDA.THFComplex in Cyclohexane in the Presence of 10 Mole % MDA

1. LDA.THF Complex Containing 10% MDA by Alkyllithium: n-Butyllithium incyclohexane (2.0 molar, 50 mls) was first charged into a reaction flaskand then reacted with 14.5 mls (0.1036 mole) diisopropylamine at <10° C.On addition of diisopropylamine, the reaction mixture did produce awhite solid precipitation of LDA. To this thick slurry 20 mls of 0.5molar (0.01 mole) magnesium bis-diisopropylamide was added, and theslurry was stirred for 15 minutes. The reaction slurry turned into aclean solution. This clean solution which contained 1.19 molar Li, 0.119molar Mg, and 1.43N active amide turned to turbid within a couple ofdays at <20° C. To this solution about 10 mls (0.12 mole) of THF wasadded, and on stirring turned back into a clean solution which remainedstable between 0° C. and room temperature for more than a couple ofweeks. Analysis of the product showed the presence of Li=1.06M, Mg=0.106M, Amide=1.28M, THF/Amide=0.99, yield=quantitative.

2. LDA.THF Complex in Cyclohexane Containing 10 Mole % MDA Made By LiMetal Route: n-Butyl-sec-butyl magnesium (DBM, 1.0 molar) in cyclohexane(100 mls) was first charged into a reaction flask along with anadditional 150 mls of cyclohexane under argon atmosphere and thenreacted with 30 mls (0.214 mole) diisopropylamine between 30° C. and 60°C. to form MDA. Next, to this reaction flask 5.8 gm (0.835 mole) lithiummetal (sand) was added at 35° C. and then reacted by adding dropwise amixture of 110 mls (0.786 mole) diisopropylamine, 78 mls (0.95 mole)THF, and 44 mls (0.384 mole) styrene, first at 38° C. for 10 minutes andthen at 30° C. over a period of 2.5 hours. The reaction slurry was thenleft overnight at room temperature under slow stirring. The next morningthe slurry was filtered to remove solids. The resulting clean filtrate(500 mls) having yellow color was analyzed. The product remained clearwithout any precipitation for a couple of months between roomtemperature and 0° C. The analysis of this product shows Li=1.48M,Mg=0.20M, THF/Amide=1.02, Amide=1.86M, yield=94.1%.

B LDA.THF Complex in H.C. Solvent Containing 5 Mole % MDA

1. Preparation of LDA.THF Complex in n-Heptane Containing 5 Mole % MDA(Made from DBM) by Lithium Metal Route: n-Butyl-sec-butyl magnesium(DBM) in n-heptane (57.5 mls, 1.05 molar) was first charged, along withan addition of pure 90 mls of n-heptane, into an oven dried one literreaction flask equipped with a dropping funnel, mechanical stirrer,thermometer, and a condenser. Next, 40 mls (0.2857 mole) ofdiisopropylamine was added under controlled rate to the reaction flaskto form soluble MDA between room and reflux temperatures. Then, thereaction flask containing MDA solution was charged with 10.0 gm (1.44mole) of lithium metal (sand). The target concentration of the endproduct may be well controlled by the addition of hydrocarbon solvent.Next, the lithium metal slurry in MDA was reacted first at 40° C.±2.0°C. by dropwise addition of a mixed solution of 110 mls (1.36 mole) THF,70 mls (0.61 mole) styrene, and 150 mls (1.07 mole) diisopropylamine.The reaction temperature was maintained between 35° and 40° C. by usingdry-ice hexane cooling bath. After initiation of Li metal reaction,several attempts were made to drop the reaction temperature to 25° C.,10° C., and 0° C. by using a cooling bath; and still the rate ofexothermic reaction was seen by rising temperatures. Finally, most ofthe reaction was carried out at room temperature (25° C.±2.0° C.).Addition rate of reactants was maintained and completed in three hours.The reaction slurry was allowed to agitate at room temperature for anadditional one hour to complete the reaction. The reaction slurrycontaining reddish solid particles and unreacted excess lithium metalwas then filtered to remove solids and yielded a yellow solution of LDA(˜510 mls). The product was analyzed. The final product (solution) wasfound to contain 2.39N active amide and 0.05 mole Mg per mole oflithium. The product was tested for thermal stability at 0° C., roomtemperature, and 40° C. for more than 30 days. Analysis of the productshowed Li=2.18M, Mg=0.11M, Amide=2.39M, THF/Amide 1.18, yield=90%.

Using the same method, two more runs were made, where in No. 1 (Exp.#6288) test 1/4 of required DIPA and all styrene/THF were added throughan addition funnel; and in No. 2 (Exp. #6292) all DIPA and 10% THF wereadded to the pot and 90% THF and all styrene were added through anaddition funnel. Analyses of these products were as follows:

    ______________________________________                                        6288                  6292                                                    ______________________________________                                        Li = 1.85 M           1.80 M                                                  Mg = 0.12 M           0.107 M                                                 Amide = 2.10 M        2.03 M                                                  THF/Amide = 1.04      1.05                                                    yield = 90            87                                                      ______________________________________                                    

C. Preparation of Soluble (1) MDA and (2) LDA.THF Complex in HydrocarbonSolvent Containing 5 Mole % MDA Products Made from One Pot ReactionUsing Mg/Na and Li Metals

Magnesium metal powder (12.5 gm, 0.515 mole), iodine crystals (0.30 gm),and n-heptane (300 mls) were charged in a reaction flask and heated toreflux temperature for 60 minutes for metal activation. Next, a metalslurry was then reacted at reflux temperature with the dropwise additionof a mixture of 70 mls (0.5 mole) diisopropylamine and 50 mls (0.48mole) n-butylchloride. The addition was completed in about 90 minutes.The reaction was completed at reflux temperature in about two additionalhours of stirring. The grayish white slurry was then cooled down to 40°C. and then 11.0 gm (0.48 mole) Na metal was added. To this slurry amixture of 55 mls (0.480 mole) styrene, 33 mls (0.40 mole) THF, and 66mls (0.47 mole) diisopropylamine were added dropwise, first at 38° C.for 10 minutes and then the remaining mixture was added in 2.5 hours at30° C. The reaction slurry was allowed to stir for an additional twohours at 30° C. and then filtered (leaving 75 mls slurry in the pot) toobtain a clean filtrate of MDA. The analysis of the MDA solution (709mls including wash solvent) was found to be 0.57 molar Mg, 1.13N activeamide, and traces of NaCl.

The reaction pot containing 75 mls of the above reaction slurrycontaining about 0.043 mole Mg as MDA and solid NaCl, unreacted metals,and other residual solid products, was charged with 7.5 gm (0.08 mole)Li metal and 150 mls n-heptane. The slurry was heated to 38° C., andthen a mixture of 57 mls (0.50 mole) styrene, 140 mls (1.0 mole)diisopropylamine, and 82.0 mls (1.0 mole) THF were added dropwise to itin about 2.5 to 3.0 hours, first at 38° C. (10 minutes) and then at 28°C.±2° C. The slurry was left overnight under slow stirring at roomtemperature before being filtered the next morning. The filtrate wasyellow orange in color. The analysis of this product shows Li=1.62M,Mg=0.086M, Amide=1.81M, IHF/Amide=1.05, yield=90%.

D. Preparation of H.C. Soluble LDA.THF Complex in Ethylbenzene/Heptanein the Presence of 3.75 Mole % MDA

MDA (60 mls, 1.10 molar) in n-heptane containing 0.32 mole THF per moleof Mg was first charged under argon atmosphere into a one liter reactionflask. Next, 10.8 gm (1.56 mole) lithium metal (sand) was charged alongwith about 260 mls of ethylbenzene. The metal slurry was then heated to40° C., and then 50 mls (0.62 mole) of THF and 100 mls (0.7143 mole)diisopropylamine were added to the reaction flask. The remaining 50 mlsof THF (0.62 mole), 96 mls (0.69 mole) DIPA, and 76 mls (0.67 mole)styrene were mixed in an addition funnel and then added dropwise to thereaction flask at 40° C.±2° C. for the first 10 minutes and then at 30°C. over a period of 2.5 hours. The temperature of the reaction wasmaintained by using a dry-ice hexane cooling bath. The reaction slurrywas then filtered after an additional three hours of stirring. Theresulting filtrate yielded (˜680 mls) as a clean, amber, reddish winecolor solution of LDA. The analysis of this product shows the presenceof Li=2.02M, Mg=0.075M, Amide=2.14M, THF/Amide=0.95, yield=94%.

Example IV Preparation of H.C. Soluble Lithium di-n-Butylamide.THFComplex Containing 5 Mole % Magnesium Bis-di-n-Butylamide in n-Heptane

Di-n-sec-butylmagnesium (28.5 mls, 1.05 molar) in n-heptane was firstcharged under argon atmosphere into a 500 ml reaction flask. Next, to itdi-n-butylamine (10 mls, 0.07 mole) was added dropwise with goodagitation between room and reflux temperatures (25° C. to 60° C.) toform soluble magnesium bis-di-n-butylamide. To this reaction flask 100mls of n-heptane and 4.52 gm (0.65 mole) lithium metal were charged at35°-40° C. The metal slurry in magnesium bis-di-n-butylamide was allowedto stir at 40° C. for one hour. The target concentration of the endproduct may be well controlled by the addition of a calculated quantityof hydrocarbon solvent. Lithium metal slurry was then reacted first at35° C.±2° C. by dropwise addition of a mixed solution of di-n-butylamine(105 mls, 0.623 mole), styrene (33 mls, 0.29 moles), and THF (45 mls,0.55 moles). The reaction temperature was varied from 0° C. to 35° C.,and still the rate of reaction was maintained good (even at lowertemperatures). Finally, reaction temperature was maintained at 30° C.±5°C. by using a cooling bath. The addition of reactants was completed overa period of 2.5 hours and was allowed to react for one additional hourto complete the reaction. The reaction slurry containing a white silkysolid were found at the end of the reaction period. Solid, silky, whiteprecipitation may have occurred due to not having enough THF to obtain asoluble product. An additional 13 mls (0.16 mole) THF was then addedunder good agitation to dissolve most of the shiny, silky solids presentin the slurry. After two hours of stirring at 30° C. the slurry wasfiltered to remove suspended solid and unreacted excess lithium metaland yielded a yellow solution of lithium di-n-butylamide containingmagnesium bis-di-n-butylamide. The final volume of the filtrate wasclose to 305 mls. The clean filtrate did produce precipitation oncooling at 0° C. overnight. Therefore, an additional 13 mls of THF (0.16mole) were added to it to obtain a thermally stable solution at 0° C.±3°C. for a few weeks. The analysis of this solution showed Li=1.62M,Mg=0.094M, Amide=1.81M, THF/Amide=1.51, yield=94%.

Example V Preparation of H.C. Soluble Lithium Pyrrolidide.THF ComplexContaining 5 Mole % Magnesium di-Pyrrolidide by Li Metal Route

Di-n-sec-butylmagnesium (60 mls, 1.23 molar) in cyclohexane was firstcharged under argon atmosphere into an oven dry one liter reactionflask. Next, 150 mls cyclohexane and 15 mls (0.180 mole) pyrrolidinewere added dropwise under good agitation between 25° C. to 60° C. Thereaction slurry was allowed to stir at 55° C.±5° C. for 45 minutes toform magnesium di-pyrrolidide which is an insoluble white solid. Theslurry temperature was brought back to 40° C. by using a cooling bath,and then 12 gms (1.73 mole) of lithium metal as dispersion incyclohexane was charged to the reaction flask. The targeted 2.0 molarconcentration of the final product solution was well controlled byadding the required volume of cyclohexane. Next, the reaction slurrycontaining lithium metal and magnesium di-pyrrolidide was reacted at 38°C. (for 10 minutes) and then at 30° C. (2.5 hours) by dropwise additionof a mixed solution of THF (125 mls, 1.525 mole), pyrrolidide (125 mls,1.5 mole), and styrene (85 mls, 0.74 mole). The color of the reactionslurry remained grayish, and the slurry turned thinner due todissolution of solid magnesium di-pyrrolidide with the formation of alithium compound. The reaction slurry was left overnight at 20° C.±5° C.under slow stirring. The next morning it was filtered to remove solidand yielded a clear yellow solution product. The total volume of thefiltrate was 745 mls having 2.03N active amide concentration. Analysisof this solution showed Li=1.79M, Mg=0.105M, Amide=1.99M, THF/Amide=102,yield=91%.

Example VI Preparation of H.C. Soluble Lithium Hexamethyldisilazade.THFComplex in n-Heptane in the Presence of 5 Mole % Magnesiumdi-Hexamethyldisilazide

Di-n-sec-butylmagnesium (50 mls, 1.05 molar) in n-heptane was firstcharged along with fresh 125 mls of n-heptane into a one liter reactionflask under argon atmosphere and then reacted with 25 mls (0.118 mole)hexamethyldisilazane between 30° C. and 86° C. (reflux) for about 45minutes. Next, 8.6 gms (1.24 mole) lithium metal (dispersion) were addedat 30° C. Next, the lithium metal slurry was reacted first at 40° C.±2°C. for 15 minutes with the dropwise addition of a mixture of styrene (65mls, 0.567 mole), THF (180 mls, 2.19 mole), HMDS (255 mls, 1.21 mole),and then at 30° C. over a period of three hours. The reaction slurry wasallowed to complete the reaction by stirring for an additional threehours at room temperature (25° C.±3° C.) before being filtered. Theresulting filtrate yielded (895 mls) as a clean solution of LHS havinglight lemon yellow color. The analysis of this product showed TotalAmide=1.13M, Mg=0.0575M, THF/Amide=2.64, Yield=80%. The LHS:THF complexwas made in pure THF medium with and without magnesium under identicalmethod as described above. The analysis of these two runs is shownbelow:

    ______________________________________                                        With Magnesium   Without Magnesium                                            ______________________________________                                        Active Amide = 1.47 M                                                                          1.50 M                                                       Mg = 0.072 M     --                                                           THF/Amide = 4.7  5.2                                                          yield = 92%      92%                                                          ______________________________________                                    

Example VII Preparation of H.C Soluble Sodium Magnesium TriDiisopropylamide in Cyclohexane by Mg/Na Metal Route A. Na₀.285 Mg₀.714(NPr₂ ^(i))₁.713.0.31THF

Magnesium metal chips (10.02 gm, 0.412 mole) iodine crystals (0.2 gm)and cyclohexane (500 mls) were charged into a one liter reaction flaskand heated to reflux (80° C.) under argon atmosphere for about one hourfor activation of metal. Next, n-butyl chloride (42 mls, 0.401 mole) anddiisopropylamine (60 mls, 0.428 mole) were added as mixed solution at acontrolled rate under good agitation. The addition of this mixedsolution was completed over a period of 90 minutes. The reaction slurrywas allowed to stir at reflux for an additional two hours to completethe reaction. The reaction slurry containing a white solid (R₂ NMgCl)was then cooled to 30° C. About 20.0 gms of sodium metal dispersion madefrom Na metal chunk was then added to the reaction slurry. Next, thereaction slurry was then reacted with a dropwise addition of a mixedsolution of styrene (60 mls, 0.52 moles), THF (15 mls, 0.1786 mole), anddiisopropylamine (95 mls, 068 mole) through an addition funnel at 35° C.The reaction temperature started rising on addition of about 10 mls ofmixed solution. The reaction temperature was maintained at 35° C. byusing cooling bath during three hours of addition time. The slurry wasallowed to stir at 35° C. for an additional two hours to complete thereaction and then filtered to remove solids. The resulting filtrateyielded 810 mls as a clear yellow solution. The analysis of this productshows Na=0.20M, Mg=0.50M, Amide=1.21M, THF/Amide=0.18.

B. Na₀.5 Mg₀.5 (NPr₂ ^(i))₁.5.1.245THF

This preparation was carried out by the same method as described in (A)using the following raw materials in order of addition:

Magnesium metal chips (10.0 gm, 0.411 mole); n-butyl chloride (40 mls,0.383 mole); diisopropylamine (60 mls, 0.428 mole); iodine crystals (0.2gm); cyclohexane (500 mls); sodium metal (20 gm); styrene (95 mls, 0.83mole); THF (80.0 mls, 0.976 mole); diisoproylamine (115 mls, 0.8215mole).

The analysis of this product showed Na=0.47M, Mg=0.43M, Amide=1.38M,THF/Amide=0.83.

Example VIII Preparation of Li_(x) Mg_(y) (NR₂ ^(i))_(z).nTHF.mLiCl inHeptane

Magnesium metal (12.95 gm, 0.533 mole), 800 mls n-heptane, and 0.25 gmiodine crystals were charged into the reaction flask under argonatmosphere and then heated to reflux temperature (98° C.±1.0° C.) forabout 60 minutes for metal activation. n-BuCl, 50 mls (0.478 mole) and70 mls (0.5 mole), of diisopropylamine were mixed in an addition funneland then added dropwise to the metal slurry at reflux temperature(60°-98° C.). Reflux temperature was dropped constantly during additionof reactants. After three hours of stirring the reaction slurrycontaining white fine solids was then cooled down to 38° C. To thisslurry 6.98 gm (1.0057 mole) of lithium metal sand was added, followedby dropwise addition of a mixture of 40 mls THF (0.4915 mole), 57 mlsstyrene (0.5 mole) and 140 mls (1.0 mole) diisopropylamine through anaddition funnel, first at 38° C. for about 15 minutes and then at 32°C.±2° in 2.5 hours. The reaction slurry was then left stirring at roomtemperature for overnight. The next morning hardly any lithium metal wasfound unreacted (nothing floating). The reaction slurry containing solidwas then filtered to yield yellow solution. The analysis of this productshowed to contain 0.45 molar magnesium, 0.6705 molar lithium, 1.6 molaractive amide and 0.228 molar chloride.

Example B

Part of the above final slurry was treated with an additional oneequivalent THF, solubilized all solid LiCl into productsolution--obtained by filtration to remove some turbid solids.

Example IX Preparation of Mo(NPr₂ ¹)₂.LiBr.2THF in Cyclohexane

Magnesium metal granular powder (12.165 gm, 0.5 mole), 450 mls ofcyclohexane and 0.3 gm iodine crystals were charged into the reactionflask under argon atmosphere and then heated to reflux temperature (80°C.±1.0°) for about one hour for metal activation. n-Butylbromide(n-BuBr), 54 mls (0.5 mole) was then added to the reaction flask atreflux temperature through an addition funnel but no significant amountof reaction between metal and n-BuBr was seen, 70 mls (0.5 mole)diisopropylamine was then added drop by drop to the reaction flask inabout 45 minutes at reflux temperature. Immediately reaction startedvigorously with the release of butane and reflux temperature was seendropping constantly during addition. Reaction was continued for threehours at reflux and three hours at room temperature. The reaction slurrycontaining white fine solids was then left overnight under slow stirringat room temperature. The next morning 290 mls (0.5 mole NBL) of n-butyllithium in cyclohexane was added dropwise to the reaction slurry at 30°C.± 2° C., followed by addition of 70 mls (0.5 moles) ofdiisopropylamine and 75 mls (0.92 mole) of THF. The rise in temperatureof the reaction slurry was noted due to the formation of magnesiumbis-diisopropylamide and lithium bromide. The reaction slurry wasstirred for about 60 minutes at room temperature. The reaction slurrycontaining a small amount of fine suspended particles was filtered toyield a clear yellow (gold) color solution product. The final volume ofthe filtrate yielded to 990 mls.

The product was analyzed: 0.462 molar total magnesium, 0.5 molarlithium, 0.5 molar bromide, 0.95N active amide and 0.925 molar THF. Theformula of product derived from the analysis is Mg(NiPr₂)₂. LiBr.₂ THF.

Example X Preparation of Soluble LiN(iPr)₂.LiBr.2.5 THF Complex inCyclohexane

50.0 mls of 2.0 Molar clear LDA.THF in cyclohexane was charged into abottle containing 8.703 gms of anhydrous LiBr and a magnetic stirrer.This mixture (slurry) was stirred for 30 minutes at room temperature,and did not dissolve any significant amount of solid. 35 mls ofcyclohexane was added to dilute, but no more solid dissolved. 4.1 mls(0.05 mole) THF was then added dropwise under good agitation for 30minutes. Some solid (about 25%) dissolved. Another 4.1 mls THF was addedand stirred for 30 minutes, which dissolved even more of the LiBr solid.But still about 25% of the solid was left undissolved after anadditional 30 minutes stirring. An additional 4.3 ml THF was added andthe mix stirred for another 30 minutes and found to dissolve more than90% of the solids, leaving a hazy (turbid) solution.

Turbidity and hazyness may be due to impurities in the anhydrous LiBr,because LiBr solubility in THF (0.32 mole LiBr/mole of THF) showed thesame kind of turbidity.

The foregoing examples illustrate some of the product variations coveredby the general formula

    M.sub.x.sup.a M.sub.y.sup.b (M.sup.c RR').sub.z.nLB.mM.sup.d X

wherein M^(a), M^(b), M^(c), M^(d), R, R', x, y, z, n and m have themeaning ascribed to them where this formula first appears herein above.The examples illustrate preferred compositions within preferred molarranges defined by selected values of x, y, z, n and m. One preferredgroup of compositions contain no lithium halide, i.e., m is zero; inthese compositions the value of x is between 0.01 to 0.99, the value ofy is between 0.99 to 0.01, z equals x+2y and n is a number which whenmultiplied by z has a value greater than zero and less than three. Inanother group of lithium halide-free compositions x is a number between0.8 and 0.99, y is between 0.2 and 0.01, z equals x+2y, n equals zmultiplied by a number between 1 and 2. Compositions containing lithiumhalide require an additional 2 moles of Lewis base such as THF for eachmole of lithium halide in the compositions. When x is zero and m isbetween zero and two, n is between zero and four. When both x and y aregreater than zero and m is greater than zero and not more than two, n isequal to m multiplied by x+2 (n=m(x+2)). When y is zero, x is 1 and m isgreater than zero and equal to or less than two, n is equal to mmultiplied by 2 plus one, n=2m+1.

What is claimed is:
 1. An alkali metal diorganoamide consistingessentially of compositions of the formula:

    M.sub.x.sup.a M.sub.y.sup.b ([M.sup.c ]NRR.sup.1).sub.z.nLB.m[M.sup.d ]LiX

wherein M^(a) is selected from lithium, sodium, potassium and mixturesthereof; M^(b) is selected from magnesium, calcium, barium, andstrontium, R and R' are independently selected from alkyl groups of 1 to10 carbon atoms, cycloalkyl groups of 4 to 10 carbon atoms, aryl groupsof 6 to 10 carbon atoms, alkylaryl groups of 7 to 12 carbon atoms,trialkylsilyl groups with alkyl groups of 1 to 5 carbons atoms,heteroalkyl groups of nitrogen, oxygen and silicon containing 3 to 10carbon atoms and heteroaryl groups of nitrogen and silicon containing 6to 12 carbon atoms and hydrogen; X is selected from chlorine, bromine,and iodine; LB is a Lewis base selected from alkyl ethers, cycloalkylethers, monoalkylamines, dialkylamines, tertiary alkylamines,cycloalkylamines and mixtures thereof; and x, y, z, n, and m representdefining molar proportions of each in relation to the whole, such thatx+y=1 and the value of x is between 0.01, z=x+2y, n is a number whichwhen multiplied by z is greater than zero but less than four, and m is anumber from zero to two and a solvating amount of a liquid hydrocarbonsolvent.
 2. A composition according to claim 1 in which M^(a) isselected from lithium, sodium and mixtures thereof, M^(b) is magnesium,R and R' are independently selected from alkyl groups of 1 to 10 carbonatoms and hydrogen so that when one of R and R' is hydrogen, NRR' is amonoalkylamine and when R and R' are both alkyl groups, NRR' is adialkylamino group, and LB is selected from cycloalkyl ethers,monoalkylamines, dialkylamines and mixtures thereof, and m is zero.
 3. Acomposition according to claim 1 in which M^(a) is selected fromlithium, sodium and mixtures thereof, M^(b) is magnesium, R and R' areboth isoalkyl groups containing three carbon atoms so that NRR' takentogether is diisopropylamino, LB is selected from the cycloalkyl ether,tetrahydrofuran, the dialkylamine diisopropylamine and mixtures thereof,the value of x is between 0.01 and 0.99, the value of y is between 0.99and 0.01, and n is a number which when multiplied by z is greater thanzero but less than three.
 4. A composition according to claim 3 in whichthe value of x is between 0.80 and 0.99, the value of y is between 0.01and 0.20 and n is z multiplied by 1.5±0.5.
 5. A composition according toclaim 1 in which M^(a) is lithium, X is selected from chlorine andbromine, M^(b) is magnesium, NRR' is diisopropylamine, Lb is selectedfrom the cycloalkyl ether tetrahydrofuran and mixtures oftetrahydrofuran with the dialkylamine, diisopropylamine, x is 0.8 to0.99, y is 0.2 to 0.01, n is m multiplied by two plus the value of x,and m is greater than zero but not greater than two.
 6. A compositionaccording to claim 3 in which the value of x is between 0.90 and 0.99and the value for y is between 0.1 and 0.01.
 7. A composition accordingto claim 3 in which x is 0.95 and y is 0.05.